What a terrific story! You really succeeded in making Jean real, believable and compelling, and retaining the essence of the Kirk character. I love her courage, her vitality, her intelligence, her ability to connect with others -- and her sexiness.  I've read more girl!Kirk stories than I care to count, but this is far and away the best. Your writing is vivid, and I applaud your decision to write it in Spock's voice in the present tense. It shows Spock's growing connection with her just perfectly. And I love the ending! 

Hope you'll be posting more here.